The debate over using public funds in political campaigns will intensify this week as Senate Republicans hold a hearing into abuses of a similar system in New York City and advocates of the measure begin attacking GOP incumbents with mail advertisements.

"The battle is joined," said Michael Kink, who leads a coalition of labor and progressive groups called A Strong Economy for All. It backs public campaign finance.

Another coalition, called Fair Elections, will begin sending fliers to voters in several districts around the state, including constituents of Sen. Hugh Farley, R-Niskayuna. The mail advertisement attacks Farley for introducing a bill backed by an industry that has contributed to his campaign account.

Touted by Gov. Andrew Cuomo in recent weeks and during his State of the State presentation in January, a voluntary system where the campaign contributions are restricted but matched with taxpayer funds has been presented as a step toward ending public corruption.

The discussions will intensify against the backdrop of looming arrests: On Friday, federal prosecutors in Brooklyn said in a court filing that they are about to reveal new details of an apparent criminal act using evidence secretly recorded by former Sen. Shirley Huntley, D-Queens. The New York Daily News named a sitting senator identified in those papers as John Sampson, D-Brooklyn.

Republicans have said the recent arrest of Queens Sen. Malcolm Smith shows the problems in a public financing system, which is currently in place in New York City. Smith has said he is innocent, but is charged with scheming to bribe GOP leaders into letting him run in the party's primary for New York City mayor. Republicans have suggested Smith, an enrolled Democrat, has no chance of winning and hatched the alleged scheme to access public funding.

The GOP will hold a Tuesday hearing on the matter, and Republicans say they oppose using taxpayer funds for political campaigns. Scott Reif, a Senate GOP spokesman, said, "the so-called 'Fair Elections' group is at it again, unfairly targeting Senator Farley, who is one of the most distinguished members in the entire Senate" and noting that one of its principal backers, the Working Families Party, remains under investigation for campaign finance violations.

Over the last five years, Farley accepted nearly $15,000 in campaign contributions from check- cashers, and introduced a bill that would allow them to issue short-term "payday" loans. Financial Services Superintendent Ben Lawsky denounced the measure, and Farley said he was no longer pushing for its enactment.

The longtime senator, who chairs the Senate's Banking Committee, said there was no connection between the contributions and the legislation. Indeed, it is common for the chairman of a committee to accept contributions from entities in its purview. Farley also defended the bill.

"These are people in a poor area that have no access to banks. In some areas, these are the only financial services that are offered," he said. "These loans are regulated. If people need loans, they're going to get it, either here, over the Internet at outrageous interest rates, or from a loan shark."

The public financing advocates are focusing on Senate Republicans, counting support from Democrats who dominate the Assembly as well as mainstream and independent Democrats in the Senate. But at least one advocate, speaking on the condition of anonymity, suggested that pushing Cuomo was key to ensuring a Senate vote.

The advocate noted national groups including the NAACP and Sierra Club, that could be helpful to a potential Cuomo presidential bid, supported the measure. The governor has persuaded Senate Republican Leader Dean Skelos to let bills to the floor in the past even when a majority of his conference-mates opposed them, most notably to legalize same-sex marriage and pass a new gun control law, and the advocate said Cuomo could threaten to denounce the coalition of Republicans and Independent Democrats that controls the flow of legislation in the Senate.

"We are not entertaining this conversation – the governor does not make policy decisions based on anything other than the merits," she said. "The idea of attempting to play politics with a public finance reform package at a time when the governor is working to clean up corruption in Albany is both ironic and absurd."